Many heating units for industrial baths are known today using the technique of compact immersed tubes.
Often, these units use burners termed "mixing at the nozzle", that is to say without distribution, the combustion being effected directly in the zone where the air and the gas meet.
Experience has, however, shown, that this type of burner is not totally satisfactory in particular on installations with compact immersed tubes and often leads to an excessive production of carbon monoxide and to a noisy operation due in particular to turbulence problems.
The Applicant has already proposed, particularly for this type of problem, some solutions, one of which is set forth in French Patent Application FR-A-2,606,492 filed on 7 Nov. 1986.